Created by: still-wait

• 问题描述：SSD检测头multi_box_head注释部分出现问题，日志/代码关键片段： Examples: .. code-block:: python

      mbox_locs, mbox_confs, box, var = fluid.layers.multi_box_head(
        inputs=[conv1, conv2, conv3, conv4, conv5, conv5],
        image=images,
        num_classes=21,
        min_ratio=20,
        max_ratio=90,
        aspect_ratios=[[2.], [2., 3.], [2., 3.], [2., 3.], [2.], [2.]],
        base_size=300,
        offset=0.5,
        flip=True,
        clip=True)

inputs最后一个参数conv5应部分应改为conv6